1. Field of the Invention
The present invention relates to a microcomputer-controlled electronic device for use as any of various video systems such as a video camera or a video tape recorder, for example.
2. Description of the Prior Art
Microcomputer-controlled electronic devices such as a video camera, a videotape recorder, or the like are often required to be adjusted when manufactured or repaired. For such adjustments, control data is supplied from an external source to the microcomputer of a microcomputer-controlled electronic device.
FIG. 1 of the accompanying drawings shows one conventional microcomputer-controlled electronic device 1 such as a video camera. The microcomputer-controlled electronic device 1 has a system controller 2 in the form of a microcomputer for controlling various circuits in the microcomputer-controlled electronic device 1. To the system controller 2, there is connected a digital-to-analog converter 3 which converts digital control data supplied from the system controller 2 into analog control data. The analog control data is supplied to a plurality of signal processors 4 (only one shown in FIG. 1) in the microcomputer-controlled electronic device 1. Each of the signal processors 4 comprises an integrated circuit (IC) for processing a signal supplied from a preceding circuit (not shown) through an input terminal 4a and supplying a processed signal to a next circuit (not shown) through an output terminal 4b.
Each of the signal processors 4 has a variable unit such as an electronic volume control unit. The variable unit has its parameter whose setting can be selected by the control data supplied from the system controller 2 through the digital-to-analog converter 3. Therefore, the settings of the variable units of the signal processors 4 can be varied by the system controller 2.
To adjust the microcomputer-controlled electronic device 1 from outside, an adjusting device 5 is connected to the electronic device 1 as shown in FIG. 1. Adjusting data is then supplied from the adjusting device 5 to the system controller 2 through an adjusting data input terminal 1a of the electronic device 1. The adjusting data supplied to the system controller 2 varies the control data produced by the system controller 2, thus adjusting the settings of the variable units of the signal processors 4 to desired values. To confirm the signal processing condition in the signal processors 4, a test signal is supplied from the adjusting device 5 through an input terminal lb to each of signal input terminals of the signal processors 4. Test signals processed by the signal processors 4 are then sent through a terminal lc back to the adjusting device 5. Therefore, the adjusting device 5 can confirm whether the settings of the variable units of the signal processors 4 are acceptable or not, based on the processed test signals fed back to the adjusting device 5.
The terminals la, lb, lc of the electronic device 1 allow the electronic device 1 to be adjusted under remote control from the adjusting device 5 without opening the electronic device 1 to expose its internal structure, and therefore are very convenient for adjustments to be made when the electronic device 5 is manufactured or repaired. However, the terminals lb, 1c connected to the input and output terminals of the signal processors 4 necessarily make the electronic device 5 complex in structure.
In the case where the electronic device 5 comprises a video system or the like which handles high-frequency signals and analog signals, the test signal tends to be affected by the length and material of signal wires by which the adjusting device 5 and the signal processors 4 are connected. For this reason, good care should be taken in selecting the signal wires for a proper assessment of the adjustments that have been made. It has therefore been difficult to adjust the electronic device 1 to an optimum condition with simple connections to and in the electronic device 1.